Three-dimensional printing ink comprising a phthalonitrile oligomer

ABSTRACT

A three-dimensional printing ink that has a viscosity suitable for three-dimensional printing, and improved performance.

The present application is a National Phase entry pursuant to 35 U.S.C. § 371 of International Application no. PCT/KR2019/012205 filed on Sep. 20, 2019, and claims priority to and the benefit of Korean Patent Application No. 10-2018-0114412 and Korean Patent Application No. 10-2018-0114413 both filed on Sep. 21, 2018 with the Korean Intellectual Property Office, the disclosures of which are herein incorporated by reference in their entirety.

FIELD

The present invention relates to three-dimensional printing ink.

BACKGROUND

Three dimensional printing (hereinafter, referred to as “3D printing”) is a process of preparing a three-dimensional object by laying binder materials one layer after another on a powder bed containing inkjet printer head.

3D printing is advantageous for multiproduct small volume production, compared to conventional mass production methods such as injection molding, and can freely make various complicated shapes or forms.

3D printing technology may be classified into a liquid-based method such as stereolithography, a powder-based method such as selective laser sintering, direct metal laser sintering, a solid-based method such as laminated object manufacturing, and fused deposition modeling, according to the kind of raw material used.

As the material for 3D printing, thermosetting resin is mainly used. For example, U.S. Pat. No. 9,708,440 (2017 Jul. 18) discloses high temperature 3D printing ink enabling 3D printing by two cure stages.

However, in general, it takes a long time for the high temperature 3D printing ink for 3D printing to be cured, and it may not have a viscosity suitable for 3D printing. Thus, there is a limitation in that additional components for accelerating curing should be used during 3D printing using high temperature 3D printing ink.

SUMMARY

It is an object of the present invention to provide three-dimensional printing ink that enables realization of viscosity suitable for three-dimensional printing and improved performance.

According to the present invention, three-dimensional printing ink is provided, which comprises (a) a phthalonitrile oligomer comprising one or more repeat units represented by the following Chemical Formula 1 and (b) a curing agent.

in the Chemical Formula 1,

R^(a) and R^(b) are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₃ hydroxyalkyl group, or a group represented by

L is a direct bond or a C₁₋₅ alkylene group unsubstituted or substituted with a C₁₋₅ alkyl group,

Z^(a) and Z^(b) are each independently, hydrogen or a group of

and at least one of Z^(a) and Z^(b) included the repeat unit represented by the Chemical Formula 1 is a group of

p is 1 to 10,

q is 0 or 1, and

n is a degree of polymerization of the repeat unit represented by the Chemical Formula 1.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows 1H-NMR spectrum data for the compound prepared in Preparation Example 1.

FIG. 2 shows 1H-NMR spectrum data for the compound prepared in Preparation Example 2.

FIG. 3 shows 1H-NMR spectrum data for the compound prepared in Preparation Example 3.

FIG. 4 shows 1H-NMR spectrum data for the compound prepared in Preparation Example 4.

FIG. 5 shows 1H-NMR spectrum data for the compound prepared in Preparation Example 5.

FIG. 6 shows 1H-NMR spectrum data for the compound prepared in Preparation Example 6.

FIG. 7 shows 1H-NMR spectrum data for the compound prepared in Preparation Example 7.

FIG. 8 shows 1H-NMR spectrum data for the compound prepared in Preparation Example 8.

DETAILED DESCRIPTION

Hereinafter, three-dimensional printing ink according to the embodiments of the invention will be explained in detail.

First, the technical the terms used herein are only to explain specific embodiments, and are not intended to limit the present invention.

A singular expression includes a plural expression thereof, unless it is expressly stated or obvious from the context that such is not intended.

As used herein, the term “comprise” is intended to designate the existence of practiced characteristic, number, step, constructional element or combinations thereof, and it is not intended to preclude the possibility of existence or addition of one or more other characteristics, numbers, steps, constructional elements or combinations thereof.

As used herein, the mark

in the Chemical Formulas means a position where a corresponding group is connected to another group.

According to one embodiment of the invention, three-dimensional printing ink is provided, which comprises (a) a phthalonitrile oligomer comprising one or more repeat units represented by the following Chemical Formula 1 and (b) a curing agent.

in the Chemical Formula 1,

R^(a) and R^(b) are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₃ hydroxyalkyl group, or a group represented by

L is a direct bond or a C₁₋₅ alkylene group unsubstituted or substituted with a C₁₋₅ alkyl group,

Z^(a) and Z^(b) are each independently, hydrogen or a group of

and at least one of Z^(a) and Z^(b) included the repeat unit represented by the Chemical Formula 1 is a group of

p is 1 to 10,

q is 0 or 1, and

n is a degree of polymerization of the repeat unit represented by the Chemical Formula 1.

As the result of continuous studies, the present inventors confirmed that a phthalonitrile oligomer comprising one or more repeat units represented by the Chemical Formula 1 has low softening point, and thus, can realize excellent processability.

The phthalonitrile oligomer has large molecular weight compared to common phthalonitrile monomers, and thus, can maintain melt viscosity above a certain level even under melting condition. Particularly, the phthalonitrile oligomer may have a melt viscosity that can be controlled within a wide range through the control of the molecular weight.

3D printing ink comprising the phthalonitrile oligomer may simultaneously have excellent wettability to a filler and appropriate melt viscosity. Thus, the 3D printing ink may be not only used per se, but also exhibit excellent processability in 3D printing applying additional components such as metal.

Hereinafter, components that can be included in the 3D printing ink will be explained.

(a) A Phthalonitrile Oligomer

According to the embodiment of the invention, in the 3D printing ink, a phthalonitrile oligomer comprising one or more repeat units represented by the following Chemical Formula 1 is included.

in the Chemical Formula 1,

R^(a) and R^(b) are each independently hydrogen, a C₁₋₅ alkyl group, a C₁₋₃ hydroxyalkyl group, or a group represented by

L is a direct bond or a C₁₋₅ alkylene group unsubstituted or substituted with a C₁₋₅ alkyl group,

Z^(a) and Z^(b) are each independently, hydrogen or a group of

and at least one of Z^(a) and Z^(b) included in the repeat unit represented by the Chemical Formula 1 is a group of

p is 1 to 10,

q is 0 or 1, and

n is a degree of polymerization of the repeat unit represented by the Chemical Formula 1.

As used herein, the term “substituted or unsubstituted” includes mono-substituted or multi-substituted with one or more substituent groups or unsubstituted.

As used herein, an “alkyl group” may be a linear chain or a branched chain. Preferably, the alkyl group has a carbon number of 1 to 5, or 1 to 3. Specifically, the alkyl group may be methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, n-pentyl, isopentyl, neopentyl, and ter-pentyl, and the like.

As used herein, a “hydroxyalkyl group” means a group wherein an alkylene group is substituted with a hydroxy group at the end. For example, the hydroxyalkyl group may be a hydroxymethyl group (—CH₂OH), a hydroxyethyl group (—CH₂CH₂OH), a hydroxypropyl group (—CH₂CH₂CH₂OH), and the like.

As used herein, an “aryl group” may be a monocyclic aryl group or a polycyclic aryl group. Preferably, the aryl group has a carbon number of 6 to 30. Specifically, the aryl group may be a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, a pyrenyl group, a perylenyl group, a chrysenyl group, and a fluorenyl group, and the like.

As used herein, a “direct bond” means that an atom does not exist at the corresponding position, and the groups of both sides are directly connected with each other.

The (a) phthalonitrile oligomer comprises one or more repeat units represented by the Chemical Formula 1.

Preferably, the (a) phthalonitrile oligomer may comprise one, or two or three repeat units represented by the Chemical Formula 1.

In case the (a) phthalonitrile oligomer comprises two or more repeat units represented by the Chemical Formula 1, the structure of each repeat unit may be different from each other.

In the Chemical Formula 1, R^(a) and R^(b) are each independently hydrogen, a C₁₋₅ alkyl group, a C₁₋₃ hydroxyalkyl group, or a group represented by

wherein L is a direct bond or a C₁₋₅ alkylene group unsubstituted or substituted with a C₁₋₅ alkyl group.

In the Chemical Formula 1, Z^(a) and Z^(b) are each independently, hydrogen or a group of

provided that at least one of Z^(a) and Z^(b) included the repeat unit represented by the Chemical Formula 1 is a group of

In the Chemical Formula 1, p is 1 to 10, or 1 to 5, or 1 to 2.

In the Chemical Formula 1, q is 0 or 1.

And, in the Chemical Formula 1, n is a degree of polymerization of the repeat unit.

According to the embodiment of the invention, the phthalonitrile oligomer may be represented by one of the following Chemical Formulas A to D.

in the Chemical Formulas A to D,

R¹ to R⁴ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₃ hydroxyalkyl group, or a group represented by

and L is a direct bond or a C₁₋₅ alkylene group unsubstituted or substituted with a C₁₋₅ alkyl group,

Z¹ to Z⁵ are each independently, hydrogen or a group of

and

at least one of Z¹ to Z⁵ in each Chemical Formula is a group of

p is 1 to 10, and

n and m are respectively, a degree of polymerization of each repeat unit.

According to the embodiment of the invention, the Chemical Formula A may be represented by the following Chemical Formulas A-1 to A-3.

in the Chemical Formula A-1 to A-3,

Z¹ to Z⁶ are each independently, hydrogen or a group of

and at least one of Z¹ to Z⁶ included in each Chemical Formula is a group of

L¹ to L³ are each independently, a C₁₋₅ alkylene group substituted with a C₁₋₅ alkyl group, and

n is a degree of polymerization of each repeat unit.

Specifically, the Chemical Formula A-3 may be represented by the following Chemical Formula (A-3)′.

In the Chemical Formula (A-3)′, Z¹ to Z⁶ are as defined in the Chemical Formula A-3.

According to the embodiment of the invention, the Chemical Formula B may be represented by the following Chemical Formula B-1.

In the Chemical Formula B-1, Z¹ to Z⁵ and n are as defined in the Chemical Formula B.

According to the embodiment of the invention, the Chemical Formula C may be represented by the following Chemical Formula C-1.

In the Chemical Formula C-1 Z¹ to Z⁵, n, and m are as defined in the Chemical Formula C.

According to the embodiment of the invention, the Chemical Formula D may be represented by the following Chemical Formula D-1.

In the Chemical Formula D, Z¹ to Z³, p and n are as defined in the Chemical Formula D.

Meanwhile, the (a) phthalonitrile oligomer may be prepared by reacting an oligomer comprising one or more repeat units represented by the following Chemical Formula 1′ (hereinafter, referred to as an “oligomer of the Chemical Formula 1′”) and a phthalonitrile compound (for example, 4-nitrophthalonitrile).

In the Chemical Formula 1′,

R^(a′) and R^(b′) are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₃ hydroxyalkyl group, or a group represented by

L is a direct bond or a C₁₋₅ alkylene group unsubstituted or substituted with a C₁₋₅ alkyl group,

p is 1 to 10,

q is 0 or 1, and

n is a degree of polymerization of the repeat unit represented by the Chemical Formula 1.

By the reaction of the oligomer of the Chemical Formula 1′ and the phthalonitrile compound, a phthalonitrile group bonds to the —OH group included in the oligomer of the Chemical Formula 1′, thereby synthesizing the (a) phthalonitrile oligomer.

In the above reaction, the amount of

groups (groups corresponding to Z^(a) and Z^(b)) introduced in the repeat units of the Chemical Formula 1 may vary according to the reaction rate of the oligomer of the Chemical Formula 1′ and the phthalonitrile compound.

As the oligomer of the Chemical Formula 1′, those prepared by a common method in the technical field to which the present invention pertains may be used.

And, as the oligomer of the Chemical Formula 1′, commercial products comprising one or more repeat units represented by the Chemical Formula 1′ may be used.

Meanwhile, the (a) phthalonitrile oligomer may have a weight average molecular weight of 1,000 g/mol to 30,000 g/mol.

Throughout the specification, the term “weight average molecular weight” is a numerical value converted in terms of standard polystyrene, measured by GPC (gel permeation chromatograph). In the specification, the term “molecular weight” means weight average molecular weight unless otherwise described.

As non-limiting examples, molecular weight is measured using Agilent PL-GPC 220 equipped with PolarGel MIXED-L column of a length of 300 mm (Polymer Laboratories). The measurement temperature is 65° C., dimethylformamide is used as a solvent, and flow rate is 1 mL/min. A sample is prepared at the concentration of 10 mg/10 mL, and then, fed in an amount of 100 μL. With reference to a calibration curve formed using polystyrene standard, Mw and Mn values are derived. As the polystyrene standard, 8 kinds having molecular weights (g/mol) of 580/3,940/8,450/31,400/70,950/316,500/956,000/4,230,000 are used.

The (a) phthalonitrile oligomer may be given molecular weight in a wide range of 1,000 g/mol to 30,000 g/mol. Through the control of the molecular weight, rheological properties of the (a) phthalonitrile oligomer such as a softening point, melt viscosity, and the like may be controlled.

Meanwhile, the 3D printing ink may further comprise a phthalonitrile compound well known in the art, in addition to the (a) phthalonitrile oligomer.

As non-limiting examples, as the phthalonitrile compound, compounds described in U.S. Pat. Nos. 4,408,035, 5,003,039, 5,003,078, 5,004,801, 5,132,396, 5,139,054, 5,208,318, 5,237,045, 5,292,854, or U.S. Pat. No. 5,350,828, and the like may be mentioned.

Preferably, the 3D printing ink may further comprise a (a′) phthalonitrile compound represented by the following Chemical Formula P1.

In the Chemical Formula P1, R^(P11) to R^(P16) are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, a group of the following Chemical Formula P2, or a group of the following Chemical Formula P3, and two or more of R^(P11) to R^(P16) are a group of the following Chemical Formula P2 or a group of the following Chemical Formula P3,

In the Chemical Formula P2,

L^(P2) is a direct bond, a C₁₋₅ alkylene group, —O—, —S—, —C(═O)—, —S(═O)—, or —S(═O)₂—,

R^(P21) to R^(P25) are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, or a cyano group, and two or more of R^(P21) to R^(P25) are cyano groups,

in the Chemical Formula P3,

L^(P3) is a direct bond, a C₁₋₅ alkylene group, —O—, —S—, —C(═O)—, —S(═O)—, or —S(═O)₂—,

R^(P31) to R^(P35) are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, or a group of the Chemical Formula P2, and one or more of R^(P31) to R^(P35) are the groups of the Chemical Formula P2.

As non-limiting examples, the (a′) phthalonitrile compound may be a compound represented by the following Chemical Formula P1′.

in the Chemical Formula P1′,

L^(P2) and L^(P3) are each independently, a direct bond, a C₁₋₅ alkylene group, —O—, —S—, —C(═O)—, —S(═O)—, or —S(═O)₂—.

R^(P11) to R^(P16), R^(P21) to R^(P25), and R^(P31) to R^(P35) are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, or a C₆₋₃₀ aryl group.

In case the 3D printing ink comprises the (a) phthalonitrile oligomer and the (a′) phthalonitrile compound represented by the Chemical Formula P1, it is preferable that the (a) phthalonitrile oligomer is included in the content of 20 wt % or more, based on the total weight of the phthalonitrile components.

Namely, in order to sufficiently obtain the effect resulting from the application of the (a) phthalonitrile oligomer, it is preferable that the (a) phthalonitrile oligomer is included in the content of 20 wt % or more, or 20 to 100 wt %, in the phthalonitrile components applied in the 3D printing ink.

The content of the (a) phthalonitrile oligomer may be controlled in the range of 20 to 100 wt % in the phthalonitrile components, as necessary (for example, according to the melt viscosity range required).

(b) A Curing Agent

According to the embodiment of the invention, the 3D printing ink comprises a curing agent.

The curing agent is a compound capable of reacting with the (a) phthalonitrile oligomer to form phthalonitrile resin.

For example, the curing agent may be a compound comprising a functional group capable of reacting with the cyano group of the (a) phthalonitrile oligomer.

Preferably, the curing agent may be a compound having one or more functional groups selected from the group consisting of an amine group, a hydroxy group and an imide group.

Specifically, the curing agent may be a compound represented by the following Chemical Formula 2.

in the Chemical Formula 2, R²¹ to R²⁶ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, an amine group, or a group of the following Chemical Formula 3, and two or more of R²¹ to R²⁶ are an amine group or a group of the following Chemical Formula 3,

in the Chemical Formula 3,

L³⁰ is a direct bond, a C₁₋₅ alkylene group, —O— or —S—,

R³¹ to R³⁵ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, or an amine group, and at least one of R³¹ to R³⁵ is an amine group.

As non-limiting examples, the curing agent may be a compound represented by the following Chemical Formula 2′.

in the Chemical Formula 2′

R²¹, R²³, R²⁴, and R²⁵ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, or a C₆₋₃₀ aryl group,

L³⁰'s are each independently, a direct bond, a C₁₋₅ alkylene group, —O— or —S—, and

R³¹ to R³⁵ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, or an amine group, and at least one of R³¹ to R³⁵ are amine groups.

And, the curing agent may be a compound represented by the following Chemical Formula 4.

in the Chemical Formula 4,

M is a tetravalent radical derived from a compound represented by any one of the following Chemical Formulas 5 to 7,

X⁴¹ and X⁴² are each independently, a divalent radical derived from a compound represented by any one of the following Chemical Formulas 8 and 9, and

n is equal to or greater than 1;

in the Chemical Formula 5, R⁵⁰ to R⁵⁵ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, or a C₆₋₃₀ aryl group;

in the Chemical Formula 6, R⁶⁰ to R⁶⁷ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, or a C₆₋₃₀ aryl group;

in the Chemical Formula 7,

R⁷⁰ to R⁷⁹ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, or a C₆₋₃₀ aryl group,

X is a direct bond, a C₁₋₅ alkylene group, —O—, —S—, —C(═O)—, —S(═O)—, —S(═O)₂—, —C(═O)—O-L¹-O—C(═O)—, -L²-C(═O)—O-L³-, -L⁴-O—C(═O)-L⁵-, or -L⁸-Ar¹-L⁷-Ar²-L⁸-, wherein L¹ to L⁸ are each independently, a direct bond, —O—, or a C₁₋₅ alkylene group; and Ar¹ and Ar² are each independently, a C₆₋₃₀ arylene group;

in the Chemical Formula 8, R⁸⁰ to R⁸⁵ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, a hydroxy group, a carboxyl group;

in the Chemical Formula 9,

R⁹⁰ to R⁹⁹ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, a hydroxy group, or a carboxyl group,

X′ is a direct bond, a C₁₋₅ alkylene group, —O—, —S—, —C(═O)—, —NR^(a)—, —S(═O)—, —S(═O)₂—, -L⁹-Ar³-L¹⁰-, or -L¹¹-Ar⁴-L¹²-Ar⁵-L¹³-, wherein R^(a) is hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, or a C₆₋₃₀ aryl group; L⁹ to L¹³ are each independently, a direct bond, —O—, or a C₁₋₅ alkylene group; and Ar³ to Ar⁵ are each independently, a C₆₋₃₀ arylene group.

As non-limiting examples, the curing agent may be a compound represented by the following Chemical Formula 4′ or Chemical Formula 4″.

in the Chemical Formulas 4′ and 4″,

X and X′ are each independently, a direct bond, a C₁₋₅ alkylene group, —O—, —S—, —C(═O)—, —S(═O)—, —S(═O)₂—, —C(═O)—O-L¹-O—C(═O)—, -L²-C(═O)—O-L³-, -L⁴-O—C(═O)-L⁵-, or -L⁸-Ar¹-L⁷-Ar²-L⁸-, wherein L¹ to L⁸ are each independently, a direct bond, —O—, or a C₁₋₅ alkylene group; Ar¹ and Ar² are each independently, a C₆₋₃₀ arylene group, and

R⁹⁰ to R⁹⁹ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, a hydroxyl group, or a carboxyl group.

Meanwhile, the content of the curing agent may be controlled in a range where curability to be given to the 3D printing ink can be secured.

As non-limiting examples, the curing agent may be included at the mole ratio of 0.01 moles to 1.5 moles per one mole of the phthalonitrile oligomer.

As non-limiting examples, the curing agent may be included at the mole ratio of 0.01 moles to 1.5 moles pre one mole of the phthalonitrile components included in the 3D printing ink. Wherein, the “phthalonitrile components” include the (a) phthalonitrile oligomer and (a′) phthalonitrile compound included in the 3D printing ink.

If the mole ratio of the curing agent increases, process window may become narrow, and thus, processability may be lowered, or high temperature curing condition may be required. And, if the mole ratio of the curing agent decreases, curability may become insufficient.

According to the embodiment of the invention, the 3D printing ink may exhibit melt viscosity of 1000 Pa·s to 100000 Pa·s by a time sweep test under temperature of 200 to 280° C. and a frequency of 1 to 10 Hz using rotational rheometer.

Meanwhile, according to the embodiment of the invention, the 3D printing ink may be provided in the state of a prepolymer, which is the reaction product of the (a) phthalonitrile oligomer and the (b) curing agent.

The prepolymer means a state wherein the reaction of the phthalonitrile oligomer and curing agent occur to some degree in the 3D printing ink (for example, a state wherein polymerization of A or B stage occurs), but completely cured state is not reached and appropriate flowability is exhibited so as to be processed.

(c) Additives

According to the embodiment of the invention, the 3D printing ink may further comprise additives.

The kind of the additives is not specifically limited.

And, the content of the additives may be controlled in a range where the properties of the 3D printing ink are not hindered.

As non-limiting examples, as the additives, metal fiber, carbon fiber, glass fiber, aramid fiber, potassium titanate fiber, celluloid fiber, sepiolite fiber, ceramic fiber, acrylic fiber, barium sulfate, calcium carbonate, zirconia, alumina, zirconium silicate, silicon dioxide, silicon carbide, graphite, carbon nanobute, titanium dioxide, polytetrafluoroethylene, tungsten disulfide, molybdenum disulfide, and milled carbon fiber, and the like may be used.

According to the present invention, three-dimensional printing ink that enables realization of viscosity suitable for three-dimensional printing and improved performance is provided.

EXAMPLES

Hereinafter, preferable examples are presented for better understanding of the invention. However, these examples are presented only as the illustrations of the invention, and the present invention is not limited thereby.

¹H-NMR (Nuclear Magnetic Resonance) Analysis

For the compounds prepared below, NMR analysis was conducted using a 500 MHz NMR spectrometer of Agilent Inc., according to the manual of the manufacturing company. The samples for NMR analysis were prepared by dissolving compounds in DMSO (dimethyl sulfoxide)-d6.

Measurement of Weight Average Molecular Weight

Using an Agilent PL-GPC 220 equipped with 300 mm PolarGel MIXED-L column (Polymer Laboratories), the weight average molecular weights (Mw) of the phthalonitrile oligomers obtained in the following Preparation Examples were measured. The results were shown in each Preparation Example.

The measurement temperature was 65° C., dimethylformamide was used as a solvent, and flow rate was 1 mL/min. A sample was prepared at the concentration of 10 mg/10 mL, and then, fed in an amount of 100 μL. With reference to a calibration curve formed using polystyrene standard, Mw and Mn values are derived. As the polystyrene standard, 8 kinds having molecular weights (g/mol) of 580/3,940/8,450/31,400/70,950/316,500/956,000/4,230,000 were used.

Preparation Example 1. Synthesis of Phthalonitrile Oligomer (PN-1)

A phthalonitrile oligomer represented by the following Chemical Formula PN-1 was synthesized as follows.

41.1 g of the oligomer represented by the Chemical Formula KA-1 (weight average molecular weight 1,360 g/mol) and 165.0 g of DMF (dimethyl formamide) were introduced into a 3 neck round bottom flask, and the mixture was stirred at room temperature to dissolve. 51.9 g of 4-nitro phthalonitrile was added thereto, 70.0 g of DMF was added, and then, the mixture was stirred to dissolve. Subsequently, 49.8 g of potassium carbonate and 30.0 g of DMF were introduced together, and the temperature was raised to 85° C. while stirring. After progressing a reaction for about 5 hours, the reaction solution was cooled to room temperature. The cooled reaction solution was poured into 0.2 N hydrochloric acid aqueous solution to neutralize and precipitate. After filtering, it was washed with water. The filtered solution was dried in a vacuum oven of 100° C. for a day. After removing water and residual solvents, a phthalonitrile oligomer represented by the Chemical Formula PN-1 (weight average molecular weight 2,000 g/mol) was obtained with the yield of 95 wt %.

The ¹H-NMR analysis result of the phthalonitrile oligomer PN-1 was shown in FIG. 1 .

Preparation Example 2. Synthesis of Phthalonitrile Oligomer (PN-2)

A phthalonitrile oligomer represented by the following Chemical Formula PN-2 was synthesized as follows.

48.0 g of the oligomer represented by the Chemical Formula NE-1 (weight average molecular weight 1,600 g/mol) and 165.0 g of DMF (dimethyl formamide) were introduced into a 3 neck round bottom flask, and the mixture was stirred at room temperature to dissolve. 48.5 g of 4-nitro phthalonitrile was added thereto, 70.0 g of DMF was added, and then, the mixture was stirred to dissolve. Subsequently, 46.4 g of potassium carbonate and 30.0 g of DMF were introduced together, and the temperature was raised to 85° C. while stirring. After progressing a reaction for about 5 hours, the reaction solution was cooled to room temperature. The cooled reaction solution was poured into 0.2 N hydrochloric acid aqueous solution to neutralize and precipitate. After filtering, it was washed with water. The filtered solution was dried in a vacuum oven of 100° C. for a day. After removing water and residual solvents, a phthalonitrile oligomer represented by the Chemical Formula PN-2 (weight average molecular weight 2,200 g/mol) was obtained with the yield of 95 wt %.

The ¹H-NMR analysis result of the phthalonitrile oligomer PN-2 was shown in FIG. 2 .

Preparation Example 3. Synthesis of Phthalonitrile Oligomer (PN-3)

An oligomer (PN-3) represented by the Chemical Formula PN-2 and having weight average molecular weight of 2,400 g/mol was obtained with the yield of 96 wt % by the same method as Preparation Example 2, except that an oligomer represented by the Chemical Formula NE-1 and having weight average molecular weight of 1,700 g/mol was used instead of the oligomer represented by the Chemical Formula NE-1 (weight average molecular weight 1,600 g/mol).

The ¹H-NMR analysis result of the phthalonitrile oligomer PN-3 was shown in FIG. 3 .

Preparation Example 4. Synthesis of Phthalonitrile Oligomer (PN-4)

A phthalonitrile oligomer represented by the following Chemical Formula PN-4 was synthesized as follows.

48.6 g of the oligomer represented by the Chemical Formula NE-1 and having weight average molecular weight 8,800 g/mol, and 155.0 g of DMF (dimethyl formamide) were introduced into a 3 neck round bottom flask, and the mixture was stirred at room temperature to dissolve. 45.2 g of 4-nitrophthalonitrile was added thereto, 70.0 g of DMF was added, and then, the mixture was stirred to dissolve. Subsequently, 43.2 g of potassium carbonate and 30.0 g of DMF were introduced together, and the temperature was raised to 85° C. while stirring. After progressing a reaction for about 5 hours, the reaction solution was cooled to room temperature. The cooled reaction solution was poured into 0.2 N hydrochloric acid aqueous solution to neutralize and precipitate. After filtering, it was washed with water. The filtered solution was dried in a vacuum oven of 100° C. for a day. After removing water and residual solvents, a phthalonitrile oligomer represented by the Chemical Formula PN-4 (weight average molecular weight 10,000 g/mol) was obtained with the yield of 90 wt %.

The ¹H-NMR analysis result of the phthalonitrile oligomer PN-4 was shown in FIG. 4 .

Preparation Example 5. Synthesis of Phthalonitrile Oligomer (PN-5)

A phthalonitrile oligomer represented by the following Chemical Formula PN-5 was synthesized as follows.

33.9 g of an oligomer represented by the Chemical Formula TD-1 (weight average molecular weight 2,700 g/mol, and 164.0 g of DMF (dimethyl formamide) were introduced into a 3 neck round bottom flask, and the mixture was stirred at room temperature to dissolve. 55.4 g of 4-nitrophthalonitrile was added thereto, 70.0 g of DMF was added, and then, the mixture was stirred to dissolve. Subsequently, 53.1 g of potassium carbonate and 30.0 g of DMF were introduced together, and the temperature was raised to 85° C. while stirring. After progressing a reaction for about 5 hours, the reaction solution was cooled to room temperature. The cooled reaction solution was poured into 0.2 N hydrochloric acid aqueous solution to neutralize and precipitate. After filtering, it was washed with water. The filtered solution was dried in a vacuum oven of 100° C. for a day. After removing water and residual solvents, a phthalonitrile oligomer represented by the Chemical Formula PN-5 (weight average molecular weight 3,500 g/mol) was obtained with the yield of 97 wt %.

The ¹H-NMR analysis result of the phthalonitrile oligomer PN-5 was shown in FIG. 5 .

Preparation Example 6. Synthesis of a Phthalonitrile Compound (PN-6)

23.3 g of 4,4′-dihydroxybiphenyl and 140 g of DMF (dimethyl formamide) were introduced into a 3 neck round bottom flask, and the mixture was stirred at room temperature to dissolve. 43.3 g of 4-nitrophthalonitrile was added thereto, 70.0 g of DMF was added, and then, the mixture was stirred to dissolve. Subsequently, 36.3 g of potassium carbonate and 30.0 g of DMF were introduced together, and the temperature was raised to 85° C. while stirring. After progressing a reaction for about 5 hours, the reaction solution was cooled to room temperature. The cooled reaction solution was poured into 0.2 N hydrochloric acid aqueous solution to neutralize and precipitate. After filtering, it was washed with water. The filtered solution was dried in a vacuum oven of 100° C. for a day. After removing water and residual solvents, a compound represented by the Chemical Formula PN-6 (4,4′-bis(3,4-dicyanophenoxy)biphenyl) was obtained with the yield of 90 wt %.

The ¹H-NMR analysis result of the PN-6 compound was shown in FIG. 6 .

Preparation Example 7. Synthesis of a Phthalonitrile Compound (PN-7)

28.0 g of bis(4-hydroxyphenyl)methane and 140 g of DMF (dimethyl formamide) were introduced into a 3 neck round bottom flask, and the mixture was stirred at room temperature to dissolve. 48.5 g of 4-nitrophthalonitrile was added thereto, 50.0 g of DMF was added, and then, the mixture was stirred to dissolve. Subsequently, 46.4 g of potassium carbonate and 30.0 g of DMF were introduced together, and the temperature was raised to 85° C. while stirring. After progressing a reaction for about 5 hours, the reaction solution was cooled to room temperature. The cooled reaction solution was poured into 0.2 N hydrochloric acid aqueous solution to neutralize and precipitate. After filtering, it was washed with water. The filtered solution was dried in a vacuum oven of 100° C. for a day. After removing water and residual solvents, a compound represented by the Chemical Formula PN-7 (4,4′-((methylenebis(4,1-phenylene))bis(oxy))diphthalonitrile) was obtained with the yield of 95 wt %.

The ¹H-NMR analysis result of the PN-7 compound was shown in FIG. 7 .

Preparation Example 8. Synthesis of a Curing Agent (CA-1)

24 g of a compound of the Chemical Formula a and 45 g of NMP (N-methyl-pyrrolidone) were introduced into a 3 neck round bottom flask, and the mixture was stirred at room temperature to dissolve. It was cooled with a water bath, and 12.4 g of a compound of the Chemical Formula b was added portionwise three times together with 45 g of NMP. When the introduced compounds were completely dissolved, 18 g of toluene was added to the reaction solution so as to form an azeotrope. Dean-Stark equipment and a reflux condenser were installed, and toluene was introduced and filled into the Dean-Stark equipment. 4.2 mL of pyridine was introduced as a dehydration condensation catalyst, the temperature was raised to 170° C., and the mixture was stirred for 3 hours.

While removing water generated with the formation of an imide ring with Dean-Stark equipment, the mixture was additionally stirred for 2 hours, and residual toluene and pyridine were removed. The reaction product was cooled to a room temperature, and precipitated in methanol to recover. The recovered precipitate was extracted with methanol to remove residual reactants, and dried in a vacuum oven to obtain a CA-1 compound represented by the Chemical Formula c with the yield of 81 wt %.

The ¹H-NMR analysis result of the CA-1 compound was shown in FIG. 8 .

Preparation Example 9. Preparation of a Curing Agent (CA-2)

A compound represented by the Chemical Formula CA-2 (1,3-bis(3-aminophenoxy)benzene, m-APB, manufactured by TCI Co., Ltd.) was prepared as a curing agent without further purification process.

Example 1

The phthalonitrile oligomer PN-1 was completely molten on a hot plate of 240° C. using an aluminum dish. A curing agent of the compound of the Chemical Formula CA-1 was added thereto such that it existed in an amount of about 0.15 moles per 1 mole of the phthalonitrile oligomer PN-1. Additionally, the mixture was uniformly mixed on a hot plate of 240° C., and then cooled to prepare 3D printing ink in the state of a prepolymer.

Example 2

3D printing ink in the state of a prepolymer was prepared by the same method as Example 1, except that a mixture of 50 wt % of the phthalonitrile oligomer PN-1 and 50 wt % of the phthalonitrile compound PN-7 was used instead of the phthalonitrile oligomer PN-1. Wherein, the curing agent of the compound of CA-1 was added such that it existed in an amount of about 0.15 moles per 1 mole of the mixture of PN-1 and PN-7.

Example 3

3D printing ink in the state of a prepolymer was prepared by the same method as Example 2, except that, based on 100 parts by weight of the mixture of the phthalonitrile oligomer PN-1 and the phthalonitrile compound PN-7, 10 parts by weight of silicon dioxide and 10 parts by weight of graphite were further added.

Example 4

3D printing ink in the state of a prepolymer was prepared by the same method as Example 1, except that a mixture of 75 wt % of the phthalonitrile oligomer PN-1 and 25 wt % of the phthalonitrile compound PN-7 was used instead of the phthalonitrile oligomer PN-1. Wherein, the curing agent of the compound of CA-1 was added such that it existed in an amount of about 0.15 moles per 1 mole of the mixture of PN-1 and PN-7.

Example 5

3D printing ink in the state of a prepolymer was prepared by the same method as Example 4, except that based on 100 parts by weight of the mixture of the phthalonitrile oligomer PN-1 and the phthalonitrile compound PN-7, 10 parts by weight of silicon dioxide and 10 parts by weight of graphite were further added.

Comparative Example 1

3D printing ink in the state of a prepolymer was prepared by the same method as Example 1, except that the phthalonitrile compound PN-6 was used instead of the phthalonitrile oligomer PN-1.

Comparative Example 2

3D printing ink in the state of a prepolymer was prepared by the same method as Example 1, except that the phthalonitrile compound PN-7 was used instead of the phthalonitrile oligomer PN-1.

TABLE 1 Curing Phthalonitrile components agent Additives (a) (a′) (b) (c) Example 1 PN-1 (100 wt %) — CA-1 — Example 2 PN-1 (50 wt %) PN-7 (50 wt %) CA-1 — Example 3 PN-1 (50 wt %) PN-7 (50 wt %) CA-1 SiO₂, graphite Example 4 PN-1 (75 wt %) PN-7 (25 wt %) CA-1 — Example 5 PN-1 (75 wt %) PN-7 (25 wt %) CA-1 SiO₂, graphite Comparative — PN-6 (100 wt %) CA-1 — Example 1 Comparative — PN-7 (100 wt %) CA-1 — Example 2

Experimental Example 1: Measurement of Melt Viscosity

The melt viscosity of 3D printing ink prepared in Examples and Comparative Examples was measured, and the results were shown in the following Table 2.

The melt viscosity was measured by a time sweep test under temperature of 200 to 280° C. and a frequency of 1 to 10 Hz using rotational rheometer.

Experimental Example 2: Evaluation of Printing Property

3D printing performance of the 3D printing ink prepared in the Examples and the Comparative Examples was evaluated. The results were shown in the following Table 2.

The 3D printing was conducted under conditions of CO₂ laser, laser intensity 1˜5%, and laser speed 100˜1000 mm/s, using a 3D printer (GEM-100, Coherent). The evaluation was made according to the following standard.

◯: The 3D printing ink is cured by laser, and can form a 3D structure.

Δ: The 3D printing ink is cured by laser, but cannot form a 3D structure (not laminated).

X: The 3D printing ink is not molten by laser, or is molten by laser but is not cured.

TABLE 2 Melt viscosity (Pa · s) 3D printing property Example 1 10000~100000 ◯ Example 2 1000~10000 Δ Example 3 10000~100000 ◯ Example 4 10000~100000 Δ Example 5 10000~100000 ◯ Comparative <1 X Example 1 Comparative <1 X Example 2

Referring to Table 2, it was confirmed that the 3D printing ink of Examples 1 to 5 has remarkably high melt viscosity, compared to Comparative Examples 1 and 2. Particularly, it was confirmed that even if the 3D printing ink of Examples 1 to 5 is molten by laser during 3D printing, it is rapidly cured by laser scan without collapse of the shape of the molten part, thereby exhibiting excellent 3D printing performance. 

The invention claimed is:
 1. A three-dimensional printing ink composition comprising: (a) a phthalonitrile oligomer comprising one or more repeat units represented by Chemical Formula 1, wherein the phthalonitrile oligomer has a weight average molecular weight of 1,000 g/mol to 30,000 g/mol, and (b) a curing agent;

wherein in the Chemical Formula 1, R^(a) and R^(b) are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₃ hydroxyalkyl group, or a group represented by

L is a direct bond or a C₁₋₅ alkylene group unsubstituted or substituted with a C₁₋₅ alkyl group, Z^(a) and Z^(b) are each independently, hydrogen or a group of

and at least one of Z^(a) and Z^(b) included in the repeat unit represented by the Chemical Formula 1 is a group of

p is 1 to 10, q is 0 or 1, and n is a degree of polymerization of the repeat unit represented by the Chemical Formula
 1. 2. The three-dimensional printing ink according to claim 1, wherein the phthalonitrile oligomer is represented by any one of Chemical Formulas A to D;

wherein in the Chemical Formulas A to D, R¹ to R⁴ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₃ hydroxyalkyl group, or a group represented by

and L is a direct bond or a C₁₋₅ alkylene group unsubstituted or substituted with a C₁₋₅ alkyl group, Z¹ to Z⁵ are each independently, hydrogen or a group of

and at least one of Z¹ to Z⁵ in each of Chemical Formulas A-D is a group of

p is 1 to 10, n and m are respectively, a degree of polymerization of each repeat unit.
 3. The three-dimensional printing ink according to claim 2, wherein the Chemical Formula A is represented by any one of Chemical Formulas A-1 to A-3;

wherein in the Chemical Formula A-1 to A-3, Z¹ to Z⁶ are each independently, hydrogen or a group of

and at least one of Z¹ to Z⁶ included in each Chemical Formula A-1 to A-3 is a group of

L¹ to L³ are each independently, a C₁₋₅ alkylene group substituted with a C₁₋₅ alkyl group, and n is a degree of polymerization of each repeat unit.
 4. The three-dimensional printing ink according to claim 2, wherein the Chemical Formula B is represented by Chemical Formula B-1;

wherein in the Chemical Formula B-1, Z¹ to Z⁵ are each independently, hydrogen or a group of

and at least one of Z¹ to Z⁵ included in the Chemical Formula B-1 is a group of

and n is a degree of polymerization of the repeat unit.
 5. The three-dimensional printing ink according to claim 2, wherein the Chemical Formula C is represented by Chemical Formula C-1;

wherein in the Chemical Formula C-1, Z¹ to Z⁵ are each independently, hydrogen or a group of

and at least one of Z¹ to Z⁵ included in the Chemical Formula C-1 is a group of

and n and m are respectively, a degree of polymerization of each repeat unit.
 6. The three-dimensional printing ink according to claim 2, wherein the Chemical Formula D is represented by Chemical Formula D-1;

wherein in the Chemical Formula D-1, Z¹ to Z³ are each independently, hydrogen or a group of

and at least one of Z¹ to Z³ included in the Chemical Formula D-1 is a group of

p is 1 to 10, and n is a degree of polymerization of the repeat unit.
 7. The three-dimensional printing ink according to claim 1, further comprising (a′) a phthalonitrile compound represented by Chemical Formula P1;

wherein in the Chemical Formula P1, R^(P11) to R^(P16) are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, a group of Chemical Formula P2, or a group of Chemical Formula P3, and two or more of the R^(P11) to R^(P16) are a group of the following Chemical Formula P2 or a group of the following Chemical Formula P3,

wherein in the Chemical Formula P2, L^(P2) is a direct bond, a C₁₋₅ alkylene group, —O—, —S—, —C(═O)—, —S(═O)—, or —S(═O)₂—, R^(P21) to R^(P25) are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, or a cyano group, and two or more of the R^(P21) to R^(P25) are cyano groups,

wherein in the Chemical Formula P3, L^(P3) is a direct bond, a C₁₋₅ alkylene group, —O—, —S—, —C(═O)—, —S(═O)—, or —S(═O)₂—, R^(P31) to R^(P35) are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, or a group of the Chemical Formula P2, and one or more of R^(P31) to R^(P35) are the groups of the Chemical Formula P2.
 8. The three-dimensional printing ink according to claim 1, wherein the curing agent has one or more functional groups selected from the group consisting of an amine group, a hydroxy group and an imide group.
 9. The three-dimensional printing ink according to claim 8, wherein the curing agent is a compound represented by Chemical Formula 2;

wherein in the Chemical Formula 2, R²¹ to R²⁶ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, an amine group, or a group of Chemical Formula 3, and two or more of R²¹ to R²⁶ are an amine group or a group of Chemical Formula 3,

wherein in the Chemical Formula 3, L³⁰ is a direct bond, a C₁₋₅ alkylene group, —O— or —S—, and R³¹ to R³⁵ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, or an amine group, and at least one of R³¹ to R³⁵ is an amine group.
 10. The three-dimensional printing ink according to claim 8, wherein the curing agent is a compound represented by Chemical Formula 4:

wherein in the Chemical Formula 4, M is a tetravalent radical derived from a compound represented by any one of Chemical Formulas 5 to 7, X⁴¹ and X⁴² are each independently, a divalent radical derived from a compound represented by any one of Chemical Formulas 8 and 9, and n is equal to or greater than 1;

wherein in the Chemical Formula 5, R⁵⁰ to R⁵⁵ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, or a C₆₋₃₀ aryl group;

wherein in the Chemical Formula 6, R⁶⁰ to R⁶⁷ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, or a C₆₋₃₀ aryl group;

wherein in the Chemical Formula 7, R⁷⁰ to R⁷⁹ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, or a C₆₋₃₀ aryl group, X is a direct bond, a C₁₋₅ alkylene group, —O—, —S—, —C(═O)—, —S(═O)—, —S(═O)₂—, —C(═O)—O-L¹-O—C(═O)—, -L²-C(═O)—O-L³-, -L⁴-O—C(═O)-L⁵-, or -L⁶-Ar¹-L⁷-Ar²-L⁸-; wherein L¹ to L⁸ are each independently, a direct bond, —O—, or a C₁₋₅ alkylene group; and Ar¹ and Ar² are each independently, a C₆₋₃₀ arylene group;

wherein in the Chemical Formula 8, R⁸⁰ to R⁸⁵ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, a hydroxy group, a carboxyl group;

wherein in the Chemical Formula 9, R⁹⁰ to R⁹⁹ are each independently, hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, a C₆₋₃₀ aryl group, a hydroxy group, or a carboxyl group, X′ is a direct bond, a C₁₋₅ alkylene group, —O—, —S—, —C(═O)—, —NR^(a)—, —S(═O)—, —S(═O)₂—, -L⁹-Ar³-L¹⁰-, or -L¹¹-Ar⁴-L¹²-Ar⁵-L¹³-; wherein R^(a) is hydrogen, a C₁₋₅ alkyl group, a C₁₋₅ alkoxy group, or a C₆₋₃₀ aryl group; L⁹ to L¹³ are each independently, a direct bond, —O—, or a C₁₋₅ alkylene group; and Ar⁴ to Ar⁵ are each independently, a C₆₋₃₀ arylene group.
 11. The three-dimensional printing ink according to claim 1, wherein the (b) curing agent is included at a mole ratio of 0.01 moles to 1.5 moles per one mole of the (a) phthalonitrile oligomer.
 12. The three-dimensional printing ink according to claim 1, wherein the three-dimensional printing ink exhibits melt viscosity of 1000 Pa·s to 100000 Pa·s by a time sweep test under temperature of 200 to 280° C. and a frequency of 1 to 10 Hz using rotational rheometer. 